Method and apparatus for production of expanded slag



May 25,1948.

w. CALDWELL 2,442,036

METHOD AND APPARATUS FOR PRODUCTION OF EXPANDED SLAG Filed- June 7, 1944 2 Sheets-Sheet 1 HIIH y 1948. w. CALDWELL 2,442,036

METHOD AND APPARATUS FOR PRODUCTION OF EXPANDED SLAG Filed June '7, 1944 'Z-"SheecS-Sheet 2 J7? 73% 07.- Mzllace J. Caldwell Patented May 25, 1948 METHOD AND ArrAnA'rnspoa-mtonpo- TION- F EXPANDED SLAG.

Wallace 1 Caldwell, Birmingham, A a; L'eo'nal- Tem leton Caldwell executr'ix" of said Wallace L. Caldwell, deceased Application June 7., 1944, Serial No. 539,219

5 Claims. 1

This invention relates to novel apparatus for treatment of any'molt'e'n slag, such as blast furna'ce'slag; electric furnace slag, copper slag, leadslag, boiler slag, glass, or'other molten slag-like material, and to a method for producing with thi'sa'pparatus an expanded slag of superior qualityforuse in the production of lightweight aggregate;

Numerous'method'sareknown for the productionzof expandedsl'a'gs. Various specific'types of apparatus havebe'en employed for the expansion of slagiby addition of water, steam or' air, or by mechanical means. Most of the'known methods for'the expansion of slag to be used as an aggre'g'ate pro'ducea product of inferior mechanical strength and of unsatisfactory durability. The main reason for the lack of adequate strength is" that the. methods of expansion which. have been employed; produce invariably an expanded slagof light weight with relativel large and irregularlysi'zedand shaped pores and a marked lack' of uniformity of structure. It has been definitely shown that in order to produce a light weight aggregate having; in addition to light weight, astronglcell structure and'fine'pores and regularly sized pores, that some further step in the processing. beyond the mere" expansion is necessary. 'I'hecont'act'ofm'olten slag with water or. steam produces some sort of expanded slag regardless of the method of contact. Usually in those cases where a small amount of water'i's used the product is a so-called popcorn slag which i'sformedin relatively large'lumps. When excess amounts of waterare used, the slag is a so-called granulated slag'which consists of small pellets: or grains.

It is an object of'this invention to provide a method and apparatus whereby the. expanded slag may befurther processed so as to form an expanded slag which, whencrushed and screened, will. provide an aggregate of exceptional quality; The process, as described herein, will produce large, irregular lumps or masses with line and uniform cell structure and of a strong'and tough quality. Aggregate is then producedfrom these" masses by customary crushing and screening equipment. I

In general my invention relates to the'produm tion of tough, light weight cellularaggregate from molten slagby disintegrating molten slag in a suitable apparatus; such as an expansion 'cham-- her, under controlledconditions regulated to form particles or pellets of" hot, plastic cellular slag andithe deliveringpf'these particles while'still' in" a" hot plastic condition and containing sum ci'ent heat" to-per'niit" themto be welded together gradually" -cool and to anneal niemsewes by itiieir containedfheatf to result in" an expanded slag of -superior*quality and strength, which may thereafter" be crushed for" use as aggregate.-

invention will be further" explained-in coh n'ction'with the accompanyin rawings which n'ldl 0T 1essidiagrammaticai1yillustrate ail 'ail rang ment-df apparatus-suitable fb'r carrying out the" method thereof.

Fig. I- isa fragmentary lan-view of an arr rangement of apparatus" for carrying out the processormy-finvention. v

Fig. 2'isaf'ragmentary-' elevation uierori Fig; 3 is a vertical section on theline fi fof Fig; 11 further dia'grsmmaticany mustache the" operation 'ofthe' apparatus.

Referringtot-lie drawings; moltenslagfrom" a runner," not illustratedf is introduced intoslag' beintroduc'ed through the conduit I2"an'd"di"scharged through'the' conduit r3. It"Wi1lbe" derstoodi that the" water jacket 1'1 is-notforth'e purpose of controlling" the temperature of the introduced" slag" but rather rar'wh'e purpose" of protecting the steel of which the inle't runner I0 it will be. understood' thatthe" funnel lo maype" composed of refractory material,

The funnel It extends through the top 1'4 of the expansion chamber" l5; andthe' slag introduced into the funnel lfi' is'discharged therefrom" withi'nthe chamber l5 inthe farm Oran annular" axially'extendingWa'terfsupplyl conduit l3, which may 'be' integral with the conduit l fwhere'by'the source of water'is from the water jacket" H," or

the conduit" 13"" in thealtferxiative may" be con: ne'ctedto'a'n externar atersuppiy scarce. The nozzle 1 His constructed andarraiiged's'o tatstfrdis""'- direction either perpendicularly to or at a downwardly inclined angle to the stream of slag as it issues from the funnel l0. This high pressure water serves to disintegrate the continuous stream of slag by the action of the water upon the molten slag to cause violent expansion thereof, and in addition the jets of water being under high pressure will throw the resulting disintegrated particles of slag to the side walls of the expansion chamber l5. As the particles of exsubjected to the action of jets of either high pressure steam, water or compressed air from peripheral jets in the tubular ring I! supplied through the conduit l8, the ring I! being mountfiecting plates 2| and through the elongated discharge opening 20 to the externally juxtaposed cooperating pair of spaced horizontally extending compressing rolls 22' which are in parallel V panded slag are thrown outwardly by the jetsof H water from nozzle [6, they maybe additionally relation to'the discharge opening 20. These -1'O1ls 22 are preferably of hollow, water cooled construction,- each being provided with for example a water inlet conduit 23 and outlet conduit 23' the rolls 22 being adapted for cooperative and joint rotation in opposed directions by means of the gears 24 and driven throughsuitable means, notwillustrated, engaged to roll shaft'2 5.

' *The rolls 22 are each provided with peripherally ed below and. in juxtaposition to the inner ter- 'SDacedradially. extending longitudinal ribs 26,

these ribs being in the'form of pyramidal or the like teeth. Although not illustrated it will be understood that in place of such teeth the rolls 22*may be provided with longitudinally extend- V ing peripherally spaced angular corrugations, the

the chamber I5 through the vent l9 which may 7 lead to a stackor exhaust'fan; not illustrated. As the molten slag is disintegrated by means of the primary jets of water issuing from the nozzle it and the secondary jets issuing from the ring H, the resulting particles or pellets are permitted to fall by gravity to the bottom of the expansion chamber i5 and deflected towards the medial elongated base discharge opening 20 by,

means of the inclined converging chamber base walls or deflecting plates 2|.

The expansion chamber i5 is primarily for the purpose of allowing for great increase in volume as the slag expands in its course downward therethrough, and maybe of 'frusto-conical, frustropyramidal or other suitable contour for such purpose; The component defining' walls of the expansion chamber l5 including the top 14 and the converging deflecting plates 2| thereof may be composed of refractory material or preferably of water-jacketsteel construction, although such details are not illustrated and. the drawings in this respect are considered to be diagrammatic. It will be understood, however, that such indicated water jacketing is not for the purpose of controlling the temperature of the slag but rather solely for cooling the steel plates when employed in contact with the hot slag to an extent necessary to prevent their destruction.

Control of the slag expansion and particle size thereof is regulated byrthe introduction of the molten slag to the funnel iii in a continuous stream and at a constant rate and by the correlation thereto of the rate of flow and quantity of water introduced by nozzle [6 and the char-'v acter and amount of supplementary expansion agent introduced through the ring I! so that when the pellets or particles of'expanded slag reach the base of expansion chamber l5 and are deflected mediallythereof by the base deflection plates 2i, they are still in a hot plastic condition retaining sufiicient heat to enablethe particles to be welded together under pressure.

As these slagparticles orfpellets in such hot plastic pressure weldable condition descend to the bottom of the .expansionchamber, they, are there grouped and directed by means of the depurpose of the rolls being'fsolely to compress and compact masses of hot plastic weldable particles or pellets of expanded cellular slag into the form' of enlarged unitary relatively densified massesfof cellular slag of fine cell structure, and the roll' teeth or corrugations being not for the purpose 7 of forming any definite shapes but for the purf-i pose of insuring an absolutely positive continuous feed for the stream of slag particles, and to progressively move them forward and to additionally provide planes of cleavage for the relatively enlarged'and compacted expanded slag;

massesso as to permit these masses toseparate and break somewhat irregularly andinto lumps along these lines of demarcation or cleavage. After the slag particles pass through and are compacted by the rolls 22; the resulting masses are permitted to drop, as diagrammatically ilj-j lustrated in Fig 3, onto the conveyor 21 which? moves beneath the rolls 22 transversely thereon As the compacted masses pass from the rollers 22, the surfaces thereof are quickly cooled by contact with the atmosphere, but remain hot on v the inside and are carried by the conveyor'2lto f cooling bins wherein they are permitted to self- 1 anneal and cool to masses of hardened and toughened materialof uniformly finecell strucej; After such annealing and cooiiing the.' masses may be subjected tojconventional crushring for use as light weight aggregate of'very and of modified refined cell structure.

high quality ture. V

I claim as my invention:

1. The method'of producing toughlight weight cellularaggregate from molten slag which come prises passing astream of molten slag in annu lar form downwardly through" ,an, expansion chamber, and therein impinging a primary'jetof Water. \under pressure inwardly ,of, and secondary jets' of. fluid under pressure outwardly of' and against said slag stream at controlled rates "and insufficient amounts 'to'reduce the coherencyj of V the slagjand to disintegrate andexpanditto'the, I

forml'of hot plasticfcellular slag particles,Icon-v tinuously delivering said particles ,by gravity 'beI-f tween opposed oppositely rotating confining. surfaces to compact, weld and mould massesio'f'z said particles while in saidhot plastic condition into enlarged unitary cellular masses, and there-' 5 after gradually cooling'said masses.

'2. Apparatus for' producing compressed of tough cellular slag of relatively uniform" and fine cell structure from molten slag, comprising a verticallyextending' expansion chamber, means for introducing a molten slag streamadjacent'the. top thereof means for impinging waterIunderm masses.

pressure against the slag stream within and adjacent the top of said chamber to disintegrate and expand the slag to cellular slag particles therein, said chamber having a base defined by convergent sides defining a constricted discharge opening for gravitational delivery of said particles while still in abut plastic condition, and compression roll means below and in close proximity to said discharge opening for receiving said particles in said condition and for compacting and welding said particles together and for delivering them in the form of enlarged unitary cellular masses.

3. Apparatus for producing compressed masses of tough cellular slag of relatively uniform and fine cell structure from molten slag, comprising a vertically extending expansion chamber, means for introducing a molten slag stream adjacent the top thereof, means for impinging jets of fluid under pressure against the slag stream within and adjacent the top of said chamber to disintegrate and expand the slag to cellular slag particles therein, a hopper-like base closure for said chamber defining an elongated horizontally extending constricted discharge opening at the base of said chamber for gravitational discharge of said particles while still in a hot plastic condition, and compression roll means parallel to and in close proximity below said discharge opening for compacting and welding said particles together and for delivering them in the form of enlarged unitary celllular masses.

4. Apparatus for producing compressed masses of tough cellular slag of relatively uniform and fine cell structure from molten slag, comprising a vertically extending expansion chamber, funnel inlet means at the top of said chamber for introducing downwardly therein a stream of molten slag, means within said chamber adjacent said inlet for impinging water under pressure against the slag stream to expand and disintegrate it to the form of cellular slag particles, said chamber having a downwardly inclined base for deflecting and collecting the particles towards an elongated horizontally extending opening formed in said base, and pressure means comprising a pair of spaced oppositely rotatable compression rolls positioned immediately below and parallel to said base opening for receiving said particles while still in a hot plastic condition and for compacting and welding said particles together and for delivering them in the form of enlarged unitary cellular masses.

5. Apparatus for producing compressed masses of tough cellular slag of relatively uniform and fine cell structure from molten slag, comprising a vertically extending expansion chamber, funnel inlet means at the top of said chamber for introducing therein downwardly an annular stream of molten slag, primary jet means within said chamber adjacent said inlet for impinging water under pressure against the slag stream, extending axially of said funnel, to expand and distintegrate the molten slag stream to the form of cellular slag particles and secondary jet means for impinging added fluid under pressure against said slag to aid in the expansion and disintegration thereof, said chamber having a downwardly inclined base for deflecting and collecting said particles, while in hot plastic condition, towards an elongated horizontally extending opening formed in said base, and means for receiving, compacting and welding said particles together and for delivering them in the form of enlarged unitary cellular masses comprising a pair of oppositely rotatable spaced compression rolls positioned below and parallel to said opening, said rolls being formed with radially projecting longitudinally extending ribs.

WALLACE L. CALDWELL.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,184,462 Larson May 23, 1916 1,458,858 Sem June 12, 1923 2,067,312 Coryell Jan. 12, 1937 2,118,707 Ingouf May 24, 1938 2,172,899 Barnard Sept. 12, 1939 2,236,691 Meinzer Apr. 1, 1941 2,382,290 Callander Aug. 14, 1945 FOREIGN PATENTS Number Country Date 143,500 Great Britain Apr. 7, 1921 227,848 Great Britain Dec. 31, 1925 

